This invention relates generally to the field of non destructive magnetic particle inspection systems and more specifically to a Apparatus for Digital measurement of Quick break voltage and Magnetic pulse duration.
Quick break is defined by the rate of decay or the fall time of the magnetic pulse in the customer's magentizing power supply coil circuit. The faster the decay of the magnetic field at the end of the pulse, the better the “quick break”. It is important to have quick break as it maximizes the sensitivity of flaw detection when using a magnetic inspection (Magnaflux) power supply system, commonly known as non destructive testing system.
This new digital quick break detector uses a microcontroller to sample the input waveform from a magnetic pick up coil, and digitally displays the result as a voltage on a LCD display, which indicates the quality of the quick break in a quantitative way . . . .
Further, at the same time as this device measures the quick break quality, it also measures the time duration of the magnetic pulse that is produced by the customer's magnetic power supply, and displays it on a LCD display.
The method of prior art for measuring quality of quick break uses a inductive pick up coil connected to a neon lamp. This method allows the lamp to flash at the end of the magnetic pulse, due to the peak voltage induced across the inductive pick up coil by the rapidly decaying magnetic field produced by the customer's magnetic power supply. The presence of a flash from the lamp indicates a “pass” condition for quick break quality of the customer's magnetic power supply. The absence of a flash from the lamp indicates a “fail” condition for the quick break quality of the customer's power supply. There is no quantitative measurement of the quick break quality, instead only a qualitative “pass/fail” indication.
The method of prior art for measuring magnetic pulse duration is using a resistive current shunt pick up for triggering timing device and measuring the duration of the current pulse produced by the customer's magnetic power supply.
For quick break quality detection, the prior art in use today is deficient for the following reasons:    1) The flashing lamp only provides a qualitative indication of the quick break quality, using a “pass/fail” indication, which does not allow the user to judge the quality of the quick break, with the precision of a quantitative digital reading, to determine with what safety margin one passes the quick break test.    2) The neon bulb firing voltage can vary significantly from one bulb to the next, causing unreliable pass or fail indications
For the magnetic pulse duration (shot time) measurement, the prior art in use today is deficient for the following reasons:    1) The transducer pick up is a resistive current shunt, which induces a voltage across this resistance as a function of the current passed through it, and this voltage is prone to noisy conditions and unreliable triggering as this shunt is not electrically isolated from the customer's magnetic power supply, hence the accuracy of the magnetic pulse duration measurement is not very accurate    2) The use of a resistive shunt for triggering is not actually measuring the magnetic pulse, but rather the current that produces the magnetic pulse, which again causes a error in the time measurement of the pulse duration